Connections for regulating the speed of alternating-current commutator-motors.



M. SGHENKEL. G THE SEEED 0P ALTERNATIN APPLICATION FILED SEPT. s

GOURRENT GOMMUTATOR MOTORS. ,-1911.

CONNECTIONS FOR REGULATIN Patented July 23,1912.

- iuonrrz so'HENKEL, or CHARLOTTENBURG, GERMANY, ASSIGNOR mo SIEMENS- SCHUCKERT WERKE, G. M. TB. H., OF BERLIN,

- GERMANY.

GERMANY, CORPORATION OF conmzorxous ron REGULATING THE srnnn or ALTERNATING-CURBENT ooiumn'ra'roit-Morons.

Specification of Letters Patent.

Patented July 23, 1912.

' Application ai'a September 6, 1911. Serial No. 64?,949.

To all whom it may concern:

Be it known thatI, Mourrz SGHENKEL, a subject of the German Emperor, and residingat Charlottenburg, near Berlin, Germany, have invented certain new and useful Improvements in Connections for Regulating the Speed of Alternating-Current Commutator-Motors, of which the following is a specification.

My invention relates to connections for regulating the. speed of alternating-current commutator motors.

The principal object ofmy invention is to avoid the use of auxiliary apparatus, such as choking coils or intermediate. transformers, in connection with polyphase alternating-current commutator motors having two sets of brushes which are displaced relatively to each other, or in which one of the sets of brushes is shifted while the other is stationary, for the purpose of regulating the speed of the motor.

It is .well known to regulate the speed of alternating current commutator motors within certain limits by shifting the brushes or by varying the voltage. Further, arrangements are ,known in which these two modes of regulation are combined by shifting the brushes of one of two sets of brushes or by holding one set of brushes stationary while the other isshifted. A change of the field and simultaneously a change of the voltage,

per turn of the rotor winding is thus brought about. By means of this expedient it is possible to regulate the speed of the motor continuously down to zero. 4

An embodiment of my inventlon is represented diagrammatically in the accom-' panying drawing.

According to my invention I avoid auxiliary devices such as choking coils or intermediate transformers by connecting each section'of the rotor winding, boundcd by a pair of brushes, in series with a section of the stator winding and by independently feedin each of these sets connected in series. n the dTflWlllfLfll 011 w, designate the stator windings of a three-phase series motor; bnb 1),, b.. and 1),, I), each designate two appertaining brushes of the two sets of brushes and T designates the second ary winding of a polyphase transformer. According to my new connection each section of the rotor is'connected together with onestator phase in series with one limb of the transformer T.

As will be readily understood, certain conductors of the rotor remain ourrentless so long as the brush I), does not coincide with the brush 1/ the brush 6 with the brush b,, and the brush 1), with the brush 6' so that here-again, as in the known arrangements, the number of operative turns of the rotor winding and withit the voltage per turn depends on the displacement of the brushes. regulate the speed of the motor it is only necessary to shift, by means of handle h, ring 1- 'which carries one set of the brushes in one or .the other direction, by which these brushes are displaced relatively to the other set so that the number of operative turns of the rotor winding is varied.

I claim 1. In a polyphase alternating current motor, the combination with the rotor having a commutator, and a plurality of sets of brushes for-said commutatormovably disposed relatively to each other for varying the speed of the motor, each section of the rotor winding bounded by two appertaining brushes of the two sets being connected through said brushes in series with a corresponding section of the stator winding, and a plurality of means corresponding in number with the stator sections, each means being arranged in series with the corresponding stator and rotor section for supplying current to said two sections.

. 2. In a polyphase alternating current mo- Thus if it should'be desired to tor, the combination with the rotor having :1 commutator, and a plurality of sets of sponding section of the stator winding, and In testimony whereof I have signed my a transformer, having a plurality of secname to this specification in the presence of ondary coils corresponding in number with two Witnesses.

the stator sections, each of said secondary MORITZ SCHENKEL. coils being arranged 1n series with one of Witnesses: the stator and rotor sections for supplying HENRY HASPER,

current to said tWo sections. ARTHUR SCHROEDER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Eetents, Washington, D. C. 

